Answer: - 7500N
Explanation:
Given the following :
Initial Velocity of car = 108km/hr
Time taken to stop after applying brakes = 4s
Mass of passengers in car = 1000kg
Force exerted by the brakes on the car =?
After 4s, then final Velocity (V) = 0
Initial Velocity (u) of the car = 108km/hr
108km/hr = (108 × 1000)m ÷ (3600)s = 30m/s
Force exerted = mass(m) × acceleration(a)
Acceleration of car = Change in Velocity with time
a = (v - u) / t
a = (0 - 30) / 4
a = - 30/ 4
a = - 7.5m/s^2
Therefore,
Force exerted = mass(m) × acceleration(a)
Force exerted = 1000kg × (-7.5)m/s^2
Force exerted = - 7500N
Answer:
The force exerted by the brakes on the motor car is -7500 N.
Explanation:
Given :-
Mass of the motor car along with passengers (m)= 1000 kgInitial velocity (u) = 108 km/hTime taken (t) = 4 sTo find :-
The force exerted by the brakes on the motor car.Solution :-
Since the car stops, the final velocity (v) will be 0 m/s.
• Initial velocity (u) = 108 km/h.
Converting initial velocity into m/s.
We know that,[tex] \sf{1\:km/h=\dfrac{5}{18}\:m/s}[/tex]
Then initial velocity,
= [108 × 5/18 ] m/s
= 30 m/s
Now find the force exerted by the brakes.
★ Formula used :
[tex]{\boxed{\sf{F=\dfrac{m(v-u)}{t}}}}[/tex]
[put values][tex]:\implies \sf \: F= \dfrac{1000(0 - 30)}{ 4} \\ \\ : \implies \sf \: F \: = \dfrac{ - 30000}{4} \\ \\ : \implies \sf \: F \: = - 7500[/tex]
The force exerted by the brakes on the motor car = -7500 N.
•The negative sign of force(F) means that the force was applied in opposite direction of motion.
__________________A force of 12N acts to the left on a body and a force of 16 N acts to the right . The size and direction of resultant force is
1)4N
2)28N to the right
3) 4 N to the right
Answer:
4 N to the rightExplanation:
The force acting to the right of the body is acting in the positive x direction while the force acting to the left of the body is acting in the negative x direction.
If a force of 12N acts to the left on a body and a force of 16 N acts to the right, force acting to the left will be -12N while that acting to the right will be +16N.
The resultant force acting on the bod will be the sum of the two forces.
Resultant = -12N+16N
Resultant = 4N
The direction of the resultant force will be towards the right since the resultant is a positive value.
Earth receives some of the Sun's energy in the form of heat and light.
What type of energy does heat and light from the Sun begin as?
O A) nuclear
OB) chemical
OC) electrical
OD) mechanical
Answer:
a) nuclear
Explanation:
One of the earliest forms of load-bearing construction is the ____ method of construction.
Answer:
the materials most often used to construct load bearing walls in large building are concrete ,block or brick . load bearing walls are one of the earliest forms of construction
A frisbee is flying through the air. Which forces are acting on it (choose 3)
Answer:
The force acting on it is lift
A rubber band that has been stretched has gained ____ energy
OA) heat
OB) kinetic
OC) potential
D) chemical
Answer: potential
Explanation:
Ahoy starting from rest moves with a distance of 200m in 10 seconds...Find the magnitude of acceleration
Answer:
The magnitude of acceleration is 2m/s² .
Explanation:
First, you have to find the velocity as it starts to travel 200m in 10s. The formula of velocity is V = Distance/Time, then you have to substitute the values into the formula :
[tex]v = d \div t[/tex]
[tex]let \: d = 200 \\ let \: t = 10[/tex]
[tex]v = 200 \div 10[/tex]
[tex]v = 20m/s[/tex]
Next, you have to substitute the values into the acceleration formula, a = (v-u)/t where v represents final velocity, u is initial velocity and t is time taken :
[tex]a = \frac{v - u}{t} [/tex]
[tex]let \: v = 20 \\ let \: u = 0 \\ let \: t = 10[/tex]
[tex]a = \frac{20 - 0}{10} [/tex]
[tex]a = \frac{20}{10} [/tex]
[tex]a = 2m/ {s}^{2} [/tex]
When is the magnitude of the acceleration of a mass on a spring at its maximum value?
A.
when the mass has a speed of zero
B.
when the mass is moving upward
C.
when the mass has no displacement
D.
when the mass is 1
2 x
Answer:
D
Explanation:
Now we know that Force is the rate of change of momentum meaning
F= mv/t
But
mv/t = Ke
v/t = ke/m
a= ke/m
Where a is acceleration
K is constant of proportionality of tension on a spring
e is the extension substended by a string.
From the formula of acceleration we can see that as mass decreases acceleration increases so we can see that m = 1
We would have a maximum value of acceleration.
The Answer Is....:
D.
A wave is sent down a thick rope that is attached to a thinner rope. What happens when the wave reaches the junction? Explain in words, or draw a diagram.
Answer:
A fraction of the wave will be reflected at the junction and the remainder will be transmitted through the junction into the thin rope
Explanation:
When the junction of the thin and the thick rope is reached by the wave, the wave behaves in the following two ways;
1) A fraction of the incident wave from the thick rope to the junction/boundary of the thin rope will be reflected back to in the direction of the thick rope with a lower amplitude and upright
2) A fraction of the incident wave from the thick rope to the junction/boundary of the thin rope will be transmitted through the thin rope such that the transmitted pulse on the thin rope will have an higher amplitude than that of the thick rope due to the available energy in the wave pulse and the lesser weight of the thin rope.
A circuit is made of a battery, a light bulb, and a 2 resistor. The battery has a voltage of 3 volts. When connected, the ammeter reads a current of 1 amp in the circuit. Find the resistance of the light bulb.
Answer:
3ohms
Explanation:
From Ohm's Law
V = IR
V is that voltage = 3volts
I = current = 1amp
R = resistance in ohms
Putting those values into the above formula.
3volts = 1amp×R
Making R the subject
R = 3/1
R = 3ohms
The resistance of the light bulb is 3ohms.
A ramp is a simple machine called the
a. wedge
b. pulley
c. inclined plane
d. lever
Answer:
Inclined Plane is the answer
Answer:
Inclined plane
Explanation:
It is called Inclined plane since it is a flat surface at an angle.
how much energy (in kW-h) does a 900 Watt stove use in a week if it is used for 1.5 hours each day?
Answer:
9.45 kWh
Explanation:
Energy = Power × time
E = 900 W × (1.5 h/day × 7 day)
E = 9450 Wh
E = 9.45 kWh
A force of 210 N is applied to an object and the object accelerates at 14m/s2. Determine the mass of the object in kg.
Answer:
15 kg
Explanation:
F = m*a
F/a = m
210/14 = 15 kg
Concrete and steel expand to almost the same amount when they are heated. Explain why you think this is lucky?
Answer:
While making a bridge or a building, the first thing that comes to our mind is that these are always made by the combination of concrete and steel. Concrete is cheap, but it has the property of breaking when it is twisted or under tension. Steel is expensive, If we made the whole thing with it, it will cost a lot. To provide strength under a reasonable cost, we use the combination of concrete and steel. Another postive point which they have together is that they both expand equally under heat, because they have the same coefficient of thermal expansion. It proves really useful, because if they had different coefficients of thermal expansions, one would expand more than the other, which will create tensions in the mixture and would break it easily. In the case, many cracks would start to appear in the bridge or buildings, which will eventually break them.
